Internet Software Consortium DHCP Distribution Version 3, Release Candidate 8 June 4, 2001 Release Notes This is a development snapshot of Version 3 of the Internet Software Consortium DHCP Distribution. NEW FEATURES Version 3 of the ISC DHCP Distribution includes the following features that are new since version 2.0: - DHCP Failover Protocol support - OMAPI, an API for accessing and modifying the DHCP server and client state. - Conditional behaviour - Storing arbitrary information on leases - Address pools with access control - Client classing - Address allocation restriction by class - Relay agent information option support - Dynamic DNS updates - Many bug fixes, performance enhancements, and minor new DHCP protocol features. This release has been beta tested quite thorougly, and we think it is substantially more robust at this time than 2.0pl5. The release candidate is expected to be free of serious bugs, but it's called a release candidate because we want people to try it and find any last real problems before we call it done. We do not expect to add anything other than documentation and any remaining bug fixes to the 3.0 release. The 3.0 Release Candidate 1 lease file is not backwards compatible with the 3.0 Beta 1 lease file, so if you have to go back, you will have to convert your lease files back to the 3.0 Beta 1 format - if you try to run a 3.0 Beta 1 server on a 3.0 lease file, it will cheerfully delete all your leases. If you are running 3.0 beta 1 and are doing dynamic DNS updates, the lease file is no longer forward-compatible to 3.0 final. A script has been provided to convert 3.0b1 lease files. This is in contrib/3.0b1-lease-convert. For information on how to install, configure and run this software, as well as how to find documentation and report bugs, please consult the README file. The Dynamic DNS Update support is a descendent of an implementation done by Lans Carstensen and Brian Dols at Rose-Hulman Institute of Technology, Jim Watt at Applied Biosystems, Irina Goble at Integrated Measurement Systems, Igor Sharfmesser at Kazakh Telecom, and Brian Murrell at BC Tel Advanced Communications. I'd like to express my thanks to all of these good people here, both for working on the code and for prodding me into improving it. Changes since 3.0 Release Candidate 7 - Fix a bug in failover where we weren't sending updates after a transition from communications-interrupted to normal. - Handle expired/released/reset -> free transition according to the protocol specification (this works - the other way not only wasn't conformant, but also didn't work). - Add a control object in both client and server that allows either daemon to be shut down cleanly. - When writing a lease, if we run out of disk space, shut down the output file and insist on writing a new one before proceeding. - In the server, if the OMAPI listener port is occupied, keep trying to get it, rather than simply giving up and exiting. - Support fetching variables from leases and also updating and adding variables to leases via OMAPI. - If two failover peers have wildly different clocks, refuse to start doing failover. - Fix a bug in the DNS update code that could cause core dumps when running on alpha processors. - Fixed a bug in ddns updates for static lease entries, thanks to a patch from Andrey M Linkevitch. - Add support for Darwin/MacOS X - Install omshell (including new documentation). - Support DNS updates in the client (this is a very obscure feature that most DHCP client users probably will not be able to use). - Somewhat cleaner status logging in the client. - Make OMAPI key naming syntax compatible with the way keys are actually named (key names are domain names). - Fix a bug in the lease file writer. - Install DHCP ISC headers in a different place than BIND 9 ISC headers, to avoid causing trouble in BIND 9 builds. - Don't send updates for attributes on an object when the attributes haven't changed. Support deleting attributes on remote objects. - Fix a number of bugs in omshell, and add the unset and refresh statements. - Handle disconnects in OMAPI a little bit more intelligently (so that the caller gets ECONNRESET instead of EINVAL). - Fix a bunch of bugs in the handling of clients that have existing leases when the try to renew their leases while failover is operating. Changes since 3.0 Release Candidate 6 - Fix a core dump that could happen when processing a DHCPREQUEST from a client that had a host declaration that contained both a fixed-address declaration and a dhcp-client-identifier option declaration, if the client identifier was longer than nine bytes. - Fix a memory leak that could happen in certain obscure cases when using omapi to manipulate leases. - Fix some bugs and omissions in omshell. Changes since 3.0 Release Candidate 5 - Fix a bug in omapi_object_dereference that prevented objects in chains from having their reference counts decreased on dereference. - Fix a bug in omapi_object_dereference that would prevent object chains from being freed upon removal of the last reference external to the chain. - Fix a number of other memory leaks in the OMAPI protocol subsystem. - Add code in the OMAPI protocol handler to trace memory leakage. - Clean up the memory allocation/reference history printer. - Support input of dotted quads and colon-seperated hex lists as attribute values in omshell. - Fix a typo in the linux interface discovery code. - Conditionalize a piece of trace code that wasn't conditional. Changes since 3.0 Release Candidate 4 - Fix a bug that would prevent leases from being abandoned properly on DHCPDECLINE. - Fix failover peer OMAPI support. - In failover, correctly handle expiration of leases. Previously, leases would never be reclaimed because they couldn't make the transition from EXPIRED to FREE. - Fix some broken failover state transitions. - Documentation fixes. - Take out an unnecessary check in DHCP relay agent information option stashing code that was preventing REBINDING clients from rebinding. - Prevent failover peers from allocating leases in DHCPREQUEST processing if the lease belongs to the other server. - Record server version in lease file introductory comment. - Correctly report connection errors in OMAPI and failover. - Make authentication signature algorithm name comparisons in OMAPI case-insensitive. - Fix compile problem on SunOS 4.x - If a signature algorithm is not termined with '.', terminate it so that comparisons between fully-qualified names will work consistently. - Different SIOCGIFCONF probe code, may "fix" problem on some Linux systems with the probe not working correctly. - Don't allow user to type omapi key on command line of omshell. Changes since 3.0 Release Candidate 3 - Do lease billing on startup in a way that I *think* will finally do the billing correctly - the previous method could overbill as a result of duplicate leases. - Document OMAPI server objects. Changes since 3.0 Release Candidate 2 Patchlevel 1 - Fix some problems in the DDNS update code. Thanks to Albert Herranz for figuring out the main problem. - Fix some reference counting errors on host entries that were causing core dumps. - Fix a byte-swap bug in the token ring code, thanks to Jochen Friedrich. - Fix a bug in lease billing, thanks to Jonas Bulow. Changes since 3.0 Release Candidate 2 - Change the conditions under which a DHCPRELEASE is actually committed to be consistent with lease binding states rather than using the lease end time. THis may fix some problems with the billing class code. - Fix a bug where lease updates would fail on Digital Unix (and maybe others) because malloc was called with a size of zero. - Fix a core dump that happens when the DHCP server can't create its trace file. Changes since 3.0 Release Candidate 1 Patchlevel 1 - Fix the dhcp_failover_put_message to not attempt to allocate a zero-length buffer. Some versions of malloc() fail if you try to allocate a zero-length buffer, and this was causing problems on, e.g., Digital Unix. - Fix a case where the failover code was printing an error message when no error had occurred. - Fix a problem where when a server went down and back up again, the peer would not see a state transition and so would stay in the non-communicating state. - Be smart about going into recover_wait. - Fix a problem in the failover implementation where peers would fail to come into sync if interrupted in the RECOVER state. This could have been the cause of some problems people have reported recently. - Fix a problem with billing classes where they would not be unbilled when the client lease expired. - If select fails, figure out which descriptor is bad, and cut it out of the I/O loop. This prevents a potentially nasty spin. I haven't heard any report it in a while, but it came up consistently in testing. - Fix a bug in the relay agent where if you specified interfaces on the command line, it would fail. - Fix a couple of small bugs in the omapi connection object (no known user impact). - Add the missing 3.0 Beta 1 lease conversion script. - Read dhcp client script hooks if they exist, rather than only if they're executable. Changes since 3.0 Release Candidate 1 - Fix a memory smash that happens when fixed-address leases are used. ANY SITE AT WHICH FIXED-ADDRESS STATEMENTS ARE BEING USED SHOULD UPGRADE IMMEDIATELY. This has been a long-standing bug - thanks to Alvise Nobile for discovering it and helping me to find it! - Fix a small bug in binary-to-ascii, thanks to H. Peter Anvin of Transmeta. - There is a known problem with the DHCP server doing failover on Compaq Alpha systems. This patchlevel is not a release candidate because of this bug. The bug should be straightforward to fix, so a new release candidate is expected shortly. - There is a known problem in the DDNS update code that is probably a bug, and is not, as far as we know, fixed in this patchlevel. Changes since 3.0 Beta 2 Patchlevel 24 - Went over problematic failover state transitions and made them all work, so that failover should now much less fragile. - Add some dhcpctl and omapi documentation - Fix compile errors when compiling with unusual predefines. - Make Token Ring work on Linux 2.4 - Fix the Digital Unix BPF_WORDALIGN bug. - Fix some dhcp client documentation errors. - Update some parts of the README file. - Support GCC on SCO. Changes since 3.0 Beta 2 Patchlevel 23 - Fix a bug in the DNS update code where a status code was not being checked. This may have been causing core dumps. - When parsing the lease file, if a lease declaration includes a billing class statement, and the lease already has a billing class, unbill the old class. - When processing failover transactions, where acks will be deferred, process the state transition immediately. - Don't try to use the new SIOCGIFCONF buffer size detection code on Linux 2.0, which doesn't provide this functionality. - Apply a patch suggested by Tuan Uong for a problem in dlpi.c. - Fix a problem in using the which command in the configure script. - Fix a parse error in the client when setting up an omapi listener. - Document the -n and -g flags to the client. - Make sure there is always a stdin and stdout on startup. This prevents shell scripts from accidentally writing error messages into configuration files that happen to be opened as stderr. - If an interface is removed, the client will now notice that it is gone rather than spinning. This has only been tested on NetBSD. - The client will attempt to get an address even if it can't create a lease file. - Don't overwrite tracefiles. - Fix some memory allocation bugs in failover. Changes since 3.0 Beta 2 Patchlevel 22 - Apply some patches suggested by Cyrille Lefevre, who is maintaining the FreeBSD ISC DHCP Distribution port. - Fix a core dump in DHCPRELEASE. Changes since 3.0 Beta 2 Patchlevel 21 - This time for sure: fix the spin described in the changes for pl20. Changes since 3.0 Beta 2 Patchlevel 20 - Fix a problem with Linux detecting large numbers of interfaces (Ben) - Fix a memory smash in the quotify code, which was introduced in pl19. - Actually fix the spin described in the changes for pl20. The previous fix only partially fixed the problem - enough to get it past the regression test. Changes since 3.0 Beta 2 Patchlevel 19 - Fix a bug that could cause the server to abort if compiled with POINTER_DEBUG enabled. - Fix a bug that could cause the server to spin when responding to a DHCPREQUEST. - Apply Joost Mulders' suggested patches for DLPI on x86. - Support NUL characters in quoted strings. - Install unformatted man pages on SunOS. Changes since 3.0 Beta 2 Patchlevel 18 - Allow the server to be placed in partner-down state using OMAPI. (Damien Neil) - Implement omshell, which can be used to do arbitrary things to the server (in theory). (Damien Neil) - Fix a case where if a client had two different leases the server could actually dereference the second one when it hadn't been referenced, leading to memory corruption and a core dump. (James Brister) - Fix a case where a client could request the address of another client's lease, but find_lease wouldn't detect that the other client had it, and would attempt to allocate it to the client, resulting in a lease conflict message. - Fix a case where a client with more than one client identifier could be given a lease where the hardware address was correct but the client identifier was not, resulting in a lease conflict message. - Fix a problem where the server could write out a colon-seperated hex list as a value for a variable, which would then not parse. The fix is to always write strings as quoted strings, with any non-printable characters quoted as octal escape sequences. So a file written the old way still won't work, but new files written this way will work. - Fix documentation for sending non-standard options. - Use unparsable names for unknown options. WARNING: this will break any configuration files that use the option-nnn convention. If you want to continue to use this convention for some options, please be sure to write a definition, like this: option option-nnn code nnn = string; You can use a descriptive name instead of option-nnn if you like. - Fix a problem where we would see a DHCPDISCOVER/DHCPOFFER/ DHCPREQUEST/DHCPACK/DHCPREQUEST/DHCPNAK sequence. This was the result of a deceptively silly bug in supersede_lease. - Fix client script exit status check, according to a fix supplied by Hermann Lauer. - Fix an endianness bug in the tracefile support, regarding ICMP messages. - Fix a bug in the client where the medium would not work correctly if it contained quoted strings. ** there was no pl17 ** Changes since 3.0 Beta 2 Patchlevel 16 - Add support for transaction tracing. This allows the state of the DHCP server on startup, and all the subsequent transactions, to be recorded in a file which can then be played back to reproduce the behaviour of the DHCP server. This can be used to quickly reproduce bugs that cause core dumps or corruption, and also for tracking down memory leaks. - Incorporate some bug fixes provided by Joost Mulders for the DLPI package which should clear up problems people have been seeing on Solaris. - Fix bugs in the handling of options stored as linked lists (agent options, fqdn options and nwip options) that could cause memory corruption and core dumps. - Fix a bug in DHCPREQUEST handling that resulted in DHCPNAK messages not being send in some cases when they were needed. - Make the lease structure somewhat more compact. - Make initial failover startup *much* faster. This was researched and implemented by Damien Neil. - Add a --version flag to all executables, which prints the program name and version to standard output. - Don't rewrite the lease file every thousand leases. - A bug in nit.c for older SunOS machines was fixed by a patch sent in by Takeshi Hagiwara. - Fix a memory corruption bug in the DHCP client. - Lots of documentation updates. - Add a feature allowing environment variables to be passed to the DHCP client script on the DHCP client command line. - Fix client medium support, which had been broken for some time. - Fix a bug in the DHCP client initial startup backoff interval, which would cause two DHCPDISCOVERS to be sent back-to-back on startup. Changes since 3.0 Beta 2 Patchlevel 15 - Some documentation tweaks. - Maybe fix a problem in the DLPI code. - Fix some error code space inconsistencies in ddns update code. - Support relay agents that intercept unicast DHCP messages to stuff agent options into them. - Fix a small memory leak in the relay agent option support code. - Fix a core dump that would occur if a packet was sent with no options. Changes since 3.0 Beta 2 Patchlevel 14 - Finish fixing a long-standing bug in the agent options code. This was causing core dumps and failing to operate correctly - in particular, agent option stashing wasn't working. Agent option stashing should now be working, meaning that agent options can be used in class statements to control address allocation. - Fix up documentation. - Fix a couple of small memory leaks that would have added up significantly in a high-demand situation. - Add a log-facility configuration parameter. - Fix a compile error on some older operating systems. - Add the ability in the client to execute certain statements before transmitting packets to the server. Handy for debugging; not much practical use otherwise. - Don't send faked-out giaddr when renewing or bound - again, useful for debugging. Changes since 3.0 Beta 2 Patchlevel 13 - Fixed a problem where the fqdn decoder would sometimes try to store an option with an (unsigned) negative length, resulting in a core dump on some systems. - Work around the Win98 DHCP client, which NUL-terminates the FQDN option. - Work around Win98 and Win2k clients that will claim they want to do the update even when they don't have any way to do it. - Fix some log messages that can be printed when failover is operating that were not printing enough information. - It was possible for a DHCPDISCOVER to get an allocation even when the state machine said the server shouldn't be responding. - Don't load balance DHCPREQUESTs from clients in RENEWING and REBINDING, since in RENEWING, if we heard it, it's for us, and in REBINDING, the client wouldn't have got to REBINDING if its primary were answering. - When we get a bogus state lease binding state transition, don't do the transition. Changes since 3.0 Beta 2 Patchlevel 12 - Fixed a couple of silly compile errors. Changes since 3.0 Beta 2 Patchlevel 11 - Albert Herranz tracked down and fixed a subtle bug in the base64 decoder that would prevent any key with an 'x' in its base64 representation from working correctly. - Thanks to Chris Cheney and Michael Sanders, we have a fix for the hang that they both spotted in the DHCP server - when one-lease-per-client was set, the code to release the "other" lease could spin. - Fix a problem with alignment of the input buffer in bpf in cases where two packets arrive in the same bpf read. - Fix a problem where the relay agent would crash if you specified an interface name on the command line. - Add the ability to conditionalize client behaviour based on the client state. - Add support for the FQDN option, and added support for a new way of doing ddns updates (ddns update style interim) that allows more than one DHCP server to update the DNS for the same network(s). This was implemented by Damien Neil with some additional functionality added by Ted Lemon. - Damien added a "log" statement, so that the configuration file can be made to log debugging information and other information. - Fixed a bug that caused option buffers not to be terminated with an end option. - Fixed a long-standing bug in the support for option spaces where the options are stored as an ordered list rather than in a hash table, which could theoretically result in memory pool corruption. - Prevent hardware declarations with no actual hardware address from being written as something unparsable, and behave correctly in the face of a null hardware address on input. - Allow key names to be FQDNs, and qualify the algorithm name if it is specified unqualified. - Modify the DDNS update code so that it never prints the "resolver failed" message, but instead says *why* the resolver failed. - Officially support the subnet selection option, which now has an RFC. - Fix a build bug on MacOS X. - Allow administrator to disable ping checking. - Clean up dhcpd.conf documentation and add more information about how it works. Changes since 3.0 Beta 2 Patchlevel 10 - Fix a bug introduced during debugging (!) and accidentally committed to CVS. Changes since 3.0 Beta 2 Patchlevel 9 - Fix DHCP client handling of vendor encapsulated options. - Fix a bug in the handling of relay agent information options introduced in patchlevel 9. - Stash agent options on client leases by default, and use the stashed options at renewal time. - Add the ability to test the client's binding state in the client configuration language. - Fix a core dump in the DNS update code. - Fix some expression evaluation bugs that were causing updates to be done when no client hostname was received. - Fix expression evaluation debugging printfs. - Teach pretty_print_option to print options in option spaces other than the DHCP option space. - Add a warning message if the RHS of a not is not boolean. - Never select for more than a day, because some implementations of select will just fail if the timeout is too long (!). - Fix a case where a DHCPDISCOVER from an unknown network would be silently dropped. - Fix a bug where if a client requested an IP address for which a different client had the lease, the DHCP server would reallocate it anyway. - Fix the DNS update code so that if the client changes its name, the DNS will be correctly updated. Changes since 3.0 Beta 2 Patchlevel 8 - Oops, there was another subtle math error in the header-length bounds-checking. Changes since 3.0 Beta 2 Patchlevel 7 - Oops, forgot to byte-swap udp header length before bounds-checking it. Changes since 3.0 Beta 2 Patchlevel 6 - Fix a possible DoS attack where a client could cause the checksummer to dump core. This was a read, not a write, so it shouldn't be possible to exploit it any further than that. - Implement client- and server-side support for using the Client FQDN option. - Support for other option spaces in the client has been added. This means that it is now possible to define a vendor option space on the client, request options in that space from the server (which must define the same option space), and then use those options in the client. This also allows NWIP and Client FQDN options to be used meaningfully. - Add object initializer support. This means that objects can now be initialized to something other than all-zeros when allocated, which makes, e.g., the interface object support code a little more robust. - Fix an off-by-one bug in the host stuffer. This was causing host deletes not the work, and may also have been causing OMAPI connections to get dropped. Thanks to James Brister for tracking this one down! - Fixed a core dump in the interface discovery code that is triggered when there is no subnet declaration for an interface, but the server decides to continue running. Thanks to Shane Kerr for tracking down and fixing this problem. Changes since 3.0 Beta 2 Patchlevel 5 - Fix a bug in the recent enhancement to the interface discovery code to support arbitrary-length interface lists. - Support NUL-terminated DHCP options when initializing client-script environment. - Fix suffix operator. - Fix NetWare/IP option parsing. - Better error/status checking in dhcpctl initialization and omapi connection code. - Fix a potential memory smash in dhcpctl code. - Fix SunOS4 and (maybe) Ultrix builds. - Fix a bug where a certain sort of incoming packet could cause a core dump on Solaris (and probably elsewhere). - Add some more safety checks in error logging code. - Add support for ISC_R_INCOMPLETE in OMAPI protocol connection code. - Fix relay agent so that if an interface is specified on the command line, the relay agent does not dump core. - Fix class matching so that match if can be combined with match or spawn with. - Do not allow spurious leases in the lease database to introduce potentially bogus leases into the in-memory database. - Fix a byte-order problem in the client hardware address type code for OMAPI. - Be slightly less picky about what sort of hardware addresses OMAPI can install in host declarations. Changes since 3.0 Beta 2 Patchlevel 4 - Incorporated Peter Marschall's proposed change to array/record parsing, which allows things like the slp-agent option to be encoded correctly. Thanks very much to Peter for taking the initiative to do this, and for doing such a careful job of it (e.g., updating the comments)! - Added an encoding for the slp-agent option. :') - Fixed SunOS 4 build. Thanks to Robert Elz for responding to my request for help on this with patches! - Incorporated a change that should fix a problem reported by Philippe Jumelle where when the network connection between two servers is lost, they never reconnect. - Fix client script files other than that for NetBSD to actually use make_resolv_conf as documented in the manual page. - Fix a bug in the packet handling code that could result in a core dump. - Fix a bug in the bootp code where responses on the local net would be sent to the wrong MAC address. Thanks to Jerry Schave for catching this one. Changes since 3.0 Beta 2 Patchlevel 3 - In the DHCP client, execute client statements prior to using the values of options, so that the client configuration can overried, e.g., the lease renewal time. - Fix a reference counting error that would result in very reproducible failures in updates, as well as occasional core dumps, if a zone was declared without a key. - Fix some Linux 2.0 compilation problems. - Fix a bug in scope evaluation during execution of "on" statements that caused values not to be recorded on leases. - If the dhcp-max-message-size option is specified in scope, and the client didn't send this option, use the one specified in scope to determine the maximum size of the response. Changes since 3.0 Beta 2 Patchlevel 2 - Fix a case where spawning subclasses were being allocated incorrectly, resulting in a core dump. - Fix a case where the DHCP server might inappropriately NAK a RENEWING client. - Fix a place dhcprequest() where static leases could leak. - Include memory.h in omapip_p.h so that we don't get warnings about using memcmp(). Changes since 3.0 Beta 2 Patchlevel 1 - Notice when SIOCFIGCONF returns more data than fit in the buffer - allocate a larger buffer, and retry. Thanks to Greg Fausak for pointing this out. - In the server, if no interfaces were configured, report an error and exit. - Don't ever record a state of 'startup'. - Don't try to evaluate the local failover binding address if none was specified. Thanks to Joseph Breu for finding this.